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The reaction of coumarins containing electron acceptor groups at position 3 (CN, CO2Et, COMe, COPh, etc.) with compounds containing active methylene groups, in particular cyanoacetamide and ethyl cyanoacetate, under Michael reaction conditions leads to the formation to 4-substituted derivatives of 3,4-dihydroxycoumarin [1]. Further reactions of these compounds gave tricyclic compounds containing an ~-pyrone ring [2] or substituted 3-(o-hydroxyphenyl)propionic acids [3].We have observed that the reaction of 3-acetyl(3-ethoxycarbonyl)coumarins Ia-b with cyanoacetylhydrazine and its Nacetyl-and N-propionyl-derivatives IIa-c under Michael conditions gave an unexpected result. The reaction product was 3cyanocoumarin (III), in yields of 32-63 % depending on the structure of the starting material.

Ethoxycarbonylacethydrazide reacts in an analogous manner. Special features have been studied of the interaction of malonic acid amide derivatives with unsubstituted coumarin and with coumarins containing electron-withdrawing groupings in position 3 of the ring.Keywords: 3-acyl(3-cyano, 3-ethoxycarbonyl)coumarins, malonic acid hydrazide and amide derivatives, mass spectrometric study of reaction products and reaction mixtures, opening and recyclization of the coumarin lactone ring, Michael reaction.Study of the interaction of 3-acyl(ethoxycarbonyl)coumarins with malonic acid dihydrazide under the conditions of the Michael reaction has shown that this reaction occurs analogously to the conversion of 3-acyl(ethoxycarbonyl)coumarins into 3-cyanocoumarins discovered by us previously [2, 3] with the formation of coumarin-3-carboxylic acid hydrazide 2.The resulting hydrazide 2, in its turn, interacts with the initial 3-acyl(ethoxycarbonyl)coumarins with the formation of salicylidene derivatives of coumarin-3-carboxylic acid hydrazides 4. The composition of the products essentially depends on the structure of the initial coumarin. In the case of coumarins unsubstituted in the benzene ring, and also their 6-methyl (6-Br) or 8-OMe derivatives, the salicylidene derivatives of coumarin-3-carboxylic acid hydrazides 4a-d predominate among the reaction products [4]. In the case of 3-ethoxycarbonyl(acetyl)coumarins the formation of the corresponding N,N'-biscoumarinoyl-2-hydrazines 3a-c was noted. These compounds are formed in insignificant amount and were not isolated in the pure state. Their presence in the reaction mixture was established by the presence in the mass spectra of the corresponding peaks for the molecular ions.

New Approach to the Synthesis of 3-Arylcoumarins.Reaction of 3-Acyl-and 3-Ethoxycarbonylcoumarins with Hydrazide of p-Nitrophenylacetic Acid.--(NEMERYUK, M. P.; DIMITROVA, V. D.; SEDOV, A. L.; ANISIMOVA, O. S.; TRAVEN, V. F.; Chem. Heterocycl.

Keywords: Michael reaction, 3-ethoxycarbonyl(acyl)coumarins, malonic acid dihydrazide, N'-salicylidene derivatives of coumarin-3-carboxylic acid, lactonc ring opening.Earlier we established that reaction of 3-ethoxycarbonyl(acyl)coumarins with cyanoacetylhydrazine and its N-derivatives under Michael reaction conditions leads to synthesis of 3-cyanocoumarins [1,2]. In an extension of this research, under similar conditions (ethanol, 70-75~ catalytic amounts of piperidine), we have studied the reaction of 3-cthoxycarbonyl-, 3-acetyl-, and 3-benzoylcoumarins la-c and also their 6-methyl-and 6(8)-methoxysubstituted derivatives ld-i with malonic acid dihydrazide 2. We have established that N'-salicylidene derivatives of coumarin-3-carboxylic acid hydrazide 3a-c are formed as a result of this reaction.R 4 R 4 3a.-r la R = OC2H5, R ~a = H; lb R = CH 3, R Ia = H; lc R = C6H5, R TM = H; ld R = OC2H5, R 3 = CH3, R 1"2'~ = H; le R = R e = CH3, R 1'3'4 = H; lfR = CrHs, R 2 = CH3, R 1"3"4 = H; lg R = OC2Hs, R 4 = OCH3, R t'2"3 = H; lh R = CH3, R 4 = OCH3, R t'2'3 = H; 1i R = C6H5, R 4 = OCH3, R 1'2'3 = H; 3a R t4 = H; 3b R 2 = CH3, R 1'2'3 = H; 3c R 4 = OCH3, R 1'2'3 = H D. I. Mendeleev Russian

The reaction of 3-ethoxycarbonylcoumarin with derivatives of cyanoacetylhydrazine directly in the sample tube of the NMR spectrometer was investigated by 1 H NMR spectroscopy. The structure of the components of the reaction mixtures was established, and their relative concentrations at the various stages of the reaction were estimated. The sequence of processes occurring in the reactions was analyzed. Both the general characteristics and the differences in the course of the reaction with cyanoacetylhydrazine or its N-isopropylidene derivative as second component were established.In a continuation of earlier researches in which the reaction of 3-ethoxycarbonylcoumarin 1 with cyanoacetylhydrazines 2 was studied by mass spectrometry [2, 3] we have investigated the reaction by 1 H NMR spectroscopy directly in the tube used to record the spectra. As second component of the reaction we used both cyanoacetylhydrazine 2a itself and its isopropylidene derivative 2b. The reaction was conducted in 1 ml of methanol-d 4 with the components 1 + 2a and 1 + 2b in an equimolar ratio.

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The reaction of 3-ethoxycarbonyl-or 3-acylcoumarins of type (I) with cyanoacetylhydrazine derivatives such as (II) affords 3-cyanocoumarins. The reaction mechanism is studied by mass spectroscopic investigations of the reaction products and mixtures. -(NEMERYUK, M. P.; DIMITROVA, V. D.; ANISIMOVA, O. S.; SEDOV, A. L.; SOLOV'EVA, N. P.; TRAVEN, V. F.; Chem. Heterocycl.